Mask for cylinder molds



May 19, 1931. o, sg u MASK FOR CYLINDER MOLDS Filed Feb. 14, 1930 I lllll :LIE

Jaw/2% Patented May 19, 1931 UNITED STATES PATENT; OFFICE umron' olsomm, or BERLIN, NEW HAMPSHIRE, ASSIGNOR 'ro BROWN comm, or BERLIN, NEW mrsnmn, A CORPORATION or MAINE 1 -shown in Figure 1.

MASK FOR CYLINDER MOZGDS Application filed February 14, 1930. Serial 1N0. 428,341.

This invention relates to paper making machinery, and more especially to mechanism for controlling locally the deposition of pulp on a cylinder mol'dso-that the thickness of the web deposited on the mold may be varied as desired from point to point on a transverse section of the web. To this end a flexible mask or apron' is provided to cover part of that portion of the mold which is presented to a pool of pulp stock. The mask is held against the mold by the pressure arising from the difference of level between the surface of the pool of stock andthe surface of the white water within the mold. According to the invention, the end edge of the mask, which may extend from one end of the mold to the other,

is suitably shaped to vary as desired the amount of pulp deposited on the mold from point to point across the web. This control may also be made adjustable by employing a mask which consists of a series of bands or'.

For a more complete understanding of the invention reference may be had to the description thereof which follows, and .to the drawings, of which,

Figure 1 represents in section a pulp stock vat with a mask embodying the invention.

Figure 2 is an and elevation of the vat Figure 3 is a diagrammatic plan of the end portion of a mask embodying the invention. 1

Figures e and 5 illustrate difierent shapes which canbe givento the free end edge of a mask.

In Figure '1 of the drawings, a cylinder mold is conventionally indicated at 10, a pulp stock vat 11 being mounted against the mold so as to present its interior to an upper quadrant of the mold. To this end the bottom 12 of the vat extends up to or against the surface of the mold. The vat is open at the and adjacent to the cylinder, and the side walls at this end have arcuate edge portions adapted to fit against the cylinder mold adjacent to the ends thereof. Within the vat 11 a pool 13 of pulp stock is normally maintained during the operation of the mechanism by the introduction of a stream of stock through a suit able feed pipe 14. The normal level of. the pulp stock may be maintained by an overflow through a lateral opening 15, an adjustable dam 16 being provided within this opening so as to vary the level of the pool as desired,

Ordinarily the loading of pulp on the surface of the cylinder takes place on that portion; of the surface which is presented to the pool, this being the portion extending from v the bottom of the vat to the free surface of the pool. According to the invention, a mask may be provided to cover a portion of the mold surface which is presented to the pool, this mask preferably extending from the bottom of the vat upwardly against the surface of the mold. By varyingthe heights to which this mask extends on the mold from point to point across the vat, or lengthwise of the mold, the thickness ofthe web of pulp picked up by the mold may be locally varied from one edge of the web to the other. This mask may take the form of a flexible sheet 17 having its free end edge suitably shaped as, 'for example, at 18 or 19 to vary thearc of; mold surface exposed to the pool from pomt to .point across the vat. Thus, for example, if

the web picked up by the cylinder mold is carried to a mandrel and wound thereon into the form of a tube, the thickness of the tube.

wall may be locally controlled from end to end as desired. By employing a mask such as is illustrated in Figure 4, the loadingof the cylinder mold would be heavier ad acent its ends than on'. the middle portion so that the ends of a tube wound from the pulp sheet thus picked up would be heavier than the a middle portion. In like manner, by employ ing a mask such as is illustrated in Figure 5, a tube is produced having thinner walls near its ends than at its middle. Thus the local loading'of pulp on the cylinder mold from end to end can be regulated by cutting the as by manipulation of the several drums' free end edge of the mask to any desired shape.

A more convenient way of exercising local control over the loading of pulp on the cylinder mold isby employing a mask such as is illustrated in Fi ures 1, 2 and 3. This mask comprises a p urality of strips arranged edge to edge, preferably from one side f t e vat to the other, or at least from one deckle on the cylinder to the other. Each of these strips has a free end portion 21 extending upwardly from a guide member 22, preferably located adjacent to the bottom 12 of the vat and also adjacent to the surface'of the cylinder 10. The strips 20 may conveniently extend alon the bottom of the vat, under a second guide member 23, and upwardly to some convenient point above the surface level of the pool 13. As shown in Figures 1 and 2, this end portion of each stnp may be wound on a suitable drum 24- which, in turn, may be mounted on a rod 25. The frictional engagement of the several drums 24 with the rod 25 may be made sufiicient to'hold each strip in adjusted position. If desired, other suitable devices may be employed for this urpose. As shown, each drum 24 is adapted to be adjustably rotated by hand so as to shorten the upward extent ofthe free end portion 21 from the bottom of the vat or to lengthen the same so as to vary the area of mold surface covered the free end of each individual strip.

24 the strips 20 may be adjusted easily while the mold is in o ration so that any local irregularities of t ickness across the pulp web may be corrected if a web of uniform thick ness is desired, or, on the other hand, any transverse variation of thickness of the'we magnbe readilly obtained.

e examp e of the latter is illustrated in Figure 3 wherein the outer strips 20 are retracted so that their free ends project up to a lesser height than those of the intermediate strips. The pulp web formed with such an arrangement of strips will have a zone of extra thickness extending in from each end for --a definite length. If the pulp web is thereupon wound on a mandrel into a tube, the resulting tube haswell defined integral formed on its ends.

An embodiment of my invention having thus been dewribed, it should be evident to those skilled in the art that many changes and modifications may be made therein without departing from its spirit or scope as defined by the appended claims.

I claim. I

1. In combination with a adapted to said mold so as to present contain a pool of stock and a cylinder mold mounted to present a portion of its surface to a pool in said vat, a mask covering a part of said portion of surface, the arc of engageshaped for local regulation of the thickness of the pulp web picked up by the mold from point to point across the web.

3. In combination, a cylinder mold, a pulp stock vat having its bottom and side walls fitted against the mold to ex se an upper quadrant of the mold to the interior of the Vet, a flexible mask within said vat extending upwardly against'the surface of said quadrant from the bottom of the vat and terminating in a free end normally below the nor mal level for a pool of stock within the vat, successive portions of said free end of the mask extending upwardly to various heights against the mold.

4. In combination with a vat adapted to contain a pool of pulp stock, and a cylinder mold mounted to present a portion of its surface to said pool, a mask coverin a part of compns said portion of surface, said mas ing a plurality of strips arranged edge to edge to cover successive areas of said surface portion, said strips being independently adjustable to vary the extents-of the several areas covered thereby.

- 5. In combination, a pulp stock vat, and a cylinder mold at one end thereof having an upper quadrant only of its surface e to the interior of said vat, a flexible mask for said mold, said mask'comp of strips arranged in side-by-sl across the vat, each strip having ae'xt'ending upwardl from vat against the sur ace of said mold to mask successive contiguous areas of said surface, and means for independently. adjusting each of said stripsto vary covered thereby. l

. 6. In combination, a cylinder mold, a pulp stock vat fitted an upper quadrant of said quadrant to the interior of the vat, a 'de member extending across the vat ad acent to the bottom thereof and adjacent to the surface of the mold, a second guide member extending e success1 'on end across the bottom of the vat, said second a plurality the bottom of the the arc of mold surface I signature.

MILTON O. SCHUR." 

